package com.DaYu;import java.util.Scanner;publicclassDemo02{publicstaticvoidmain(String[] args){
JuiceMachine jm =newJuiceMachine();
Apple a =newApple();
jm.makeJuice(a);
WaterMelon wm =newWaterMelon();
jm.makeJuice(wm);
Fruit fruit =newApple();
jm.makeJuice(fruit);
Fruit fruit1 =newOrange();
jm.makeJuice(fruit1);}}classJuiceMachine{//参数为父类引用,免去了定义以各种水果为参数的繁琐publicvoidmakeJuice(Fruit fruit){
fruit.flow();}}classFruit{publicvoidflow(){
System.out.println("流出果汁");}}classAppleextendsFruit{publicvoidflow(){
System.out.println("流出苹果汁");}}classWaterMelonextendsFruit{publicvoidflow(){
System.out.println("流出西瓜汁");}}classOrangeextendsFruit{publicvoidflow(){
System.out.println("流出橙子汁");}}